Ed Lee says he's not sure why protesters in Hong Kong are agitated.

Receive the latest local updates in your inbox

Mayor Ed Lee isn't taking a position on the protests in Hong Kong, which he says he "hasn't studied."

Pro-Hong Kong demonstrators in San Francisco were incensed to learn of a man in a high place hoisting the flag of their opponents, the "autocratic" Peoples Republic of China: Mayor Ed Lee raised the red flag at City Hall on Thursday.

Lee, the first Chinese-American mayor of a major American city, was honoring China's National Day at a ceremony that featured Nansheng Yuan, China's consul general, the San Francisco Chronicle reported.

On the same day, about 150 pro-Hong Kong demonstrators protested outside the Hong Kong Economic Trade Office in San Francisco, the newspaper reported, while tens of thousands, if not more, took to the streets in Hong Kong.

Hong Kong has close ties to San Francisco's Cantonese-speaking Chinese community, though in recent years the city has also become home to Mandarin speakers from the mainland.

Lee told the Chronicle that he was not sure why Occupy Central had shut down much of Hong Kong for the last week, and the mayor also shied away from taking a stance on the issue, despite a long history of San Francisco elected officials going on record in support of democracy.

Occupy Central is protesting increased control from the Beijing-based government. Specifically, the Hong Kong protesters are demonstrating against Beijing selecting the candidates for chief executive, the semi-autonomous city's top leader.

Lee said "voices have to be heard and negotiations have to be handled in a delicate way," but that meanwhile it was not inappropriate to honor the city's "close ties" with China.